Living Vinyl-Addition Polymerization of Norbornenes Unveiled by Catalytic Environment Control

Living vinyl-addition polymerization (VAP) of norbornene (NB) derivatives has been regarded as a route to structurally well-defined vinyl-addition polynorbornenes (VA-PNBs), yet achieving both high catalytic activity and living characteristics remains challenging. While previous studies have primarily sought solutions through catalyst design, our recent work suggests that the environment in which a catalyst operates can be equally important. By controlling the catalytic environment surrounding palladium(II) active species, the VAP of NBs proceeded with improved living characteristics over a broad molar mass range while maintaining high monomer conversion. The resulting VA-PNBs exhibited controlled molar masses, narrow molar mass distributions, and the ability to form block copolymers through sequential monomer addition. This level of molecular control enabled the synthesis of model VA-PNBs, providing desirable materials for investigating how subtle molecular variations influence thermal, mechanical, and dielectric properties